Consolidated Statements of Changes in Shareholders' Equity (unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2011	$ 41,435	$ 21,447	$ (709)	$ 62,173
Balance (in shares) at Dec. 31, 2011	13,531,832
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net changes in unrealized loss on available for sale securities, net of income tax expense (benefits)			356	356
Common stock dividends	334	(334)		0
Common stock dividends (in shares)	135,320
Stock-based compensation expense	5			5
Net Income		1,051		1,051
Balance at Mar. 31, 2012	41,774	22,164	(353)	63,585
Balance (in shares) at Mar. 31, 2012	13,667,152
Balance at Dec. 31, 2011	41,435	21,447	(709)	62,173
Balance (in shares) at Dec. 31, 2011	13,531,832
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net changes in unrealized loss on available for sale securities, net of income tax expense (benefits)			645	645
Net changes in unrecognized past service Costs of employee benefit plans, net income tax benefits			(203)	(203)
Common stock dividends	1,003	(1,003)
Common stock dividends (in shares)	415,390
Common stock issuance	383			383
Common stock issuance (in shares)	134,761
Stock-based compensation expense	13			13
Net Income		5,018		5,018
Balance at Dec. 31, 2012	43,173	26,179	89	69,441
Balance (in shares) at Dec. 31, 2012	14,217,303			14,217,303
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net changes in unrealized loss on available for sale securities, net of income tax expense (benefits)			(66)	(66)
Net changes in unrecognized past service Costs of employee benefit plans, net income tax benefits			11	11
Common stock dividends	619	(619)
Common stock dividends (in shares)	142,157
Stock-based compensation expense	4			4
Net Income		1,075		1,075
Balance at Mar. 31, 2013	$ 43,796	$ 26,635	$ 34	$ 70,465
Balance (in shares) at Mar. 31, 2013	14,359,460			14,359,460